Hi guys,
It is fairly 'normal' for the DVBT receiver dongle to run pretty hot, though not normally so hot that you can't touch the plug, but being metal, it will of course act as a 'heat sink' and absorb any heat generated by the board. The high heat level caused quite a lot of concern in the early days but very few failures. I know Paul Sengupta has changed over from an MCX plug to a solder mount SMA connector (the same as used for the P3i antenna), which being a screw connector is not susceptible to coming loose and pulling out as can happen with the MRX. Means you also need to change the corresponding plug on your 1090MHz antenna (not particularly easy) or buy an alternative 1090MHz antenna with a matching SMA connector of course.
Regards
Peter